Рейтинг 5 из 5 звёзд
This WAS truly the best youtube downloader I ever used until it updated itself a few days ago, causing it to no longer work.
The SOLUTION (that works for now, anyways):
Download and install Version 5 . 7 . 31 or older and TURN OFF AUTOMATIC UPDATES.
Hope this helps someone.
By the way, Complete Youtube Saver obviously doesn't work with Firefox Quantum (yet), but it DOES STILL WORK with Pale Moon. A lot of the other popular Firefox Add-Ons work with Pale Moon, too.